--- /dev/null
+From 925ea0fa5277c1e6bb9e51955ef34eea9736c3d7 Mon Sep 17 00:00:00 2001
+From: Tony Lindgren <tony@atomide.com>
+Date: Thu, 12 May 2022 16:15:06 +0300
+Subject: tty: n_gsm: Fix packet data hex dump output
+
+From: Tony Lindgren <tony@atomide.com>
+
+commit 925ea0fa5277c1e6bb9e51955ef34eea9736c3d7 upstream.
+
+The module param debug for n_gsm uses KERN_INFO level, but the hexdump
+now uses KERN_DEBUG level. This started after commit 091cb0994edd
+("lib/hexdump: make print_hex_dump_bytes() a nop on !DEBUG builds").
+We now use dynamic_hex_dump() unless DEBUG is set.
+
+This causes no packets to be seen with modprobe n_gsm debug=0x1f unlike
+earlier. Let's fix this by adding gsm_hex_dump_bytes() that calls
+print_hex_dump() with KERN_INFO to match what n_gsm is doing with the
+other debug related output.
+
+Fixes: 091cb0994edd ("lib/hexdump: make print_hex_dump_bytes() a nop on !DEBUG builds")
+Cc: Stephen Boyd <swboyd@chromium.org>
+Signed-off-by: Tony Lindgren <tony@atomide.com>
+Link: https://lore.kernel.org/r/20220512131506.1216-1-tony@atomide.com
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/tty/n_gsm.c | 31 +++++++++++++++++++++++--------
+ 1 file changed, 23 insertions(+), 8 deletions(-)
+
+--- a/drivers/tty/n_gsm.c
++++ b/drivers/tty/n_gsm.c
+@@ -444,6 +444,25 @@ static u8 gsm_encode_modem(const struct
+ return modembits;
+ }
+
++static void gsm_hex_dump_bytes(const char *fname, const u8 *data,
++ unsigned long len)
++{
++ char *prefix;
++
++ if (!fname) {
++ print_hex_dump(KERN_INFO, "", DUMP_PREFIX_NONE, 16, 1, data, len,
++ true);
++ return;
++ }
++
++ prefix = kasprintf(GFP_KERNEL, "%s: ", fname);
++ if (!prefix)
++ return;
++ print_hex_dump(KERN_INFO, prefix, DUMP_PREFIX_OFFSET, 16, 1, data, len,
++ true);
++ kfree(prefix);
++}
++
+ /**
+ * gsm_print_packet - display a frame for debug
+ * @hdr: header to print before decode
+@@ -508,7 +527,7 @@ static void gsm_print_packet(const char
+ else
+ pr_cont("(F)");
+
+- print_hex_dump_bytes("", DUMP_PREFIX_NONE, data, dlen);
++ gsm_hex_dump_bytes(NULL, data, dlen);
+ }
+
+
+@@ -698,9 +717,7 @@ static void gsm_data_kick(struct gsm_mux
+ }
+
+ if (debug & 4)
+- print_hex_dump_bytes("gsm_data_kick: ",
+- DUMP_PREFIX_OFFSET,
+- gsm->txframe, len);
++ gsm_hex_dump_bytes(__func__, gsm->txframe, len);
+ if (gsmld_output(gsm, gsm->txframe, len) <= 0)
+ break;
+ /* FIXME: Can eliminate one SOF in many more cases */
+@@ -2448,8 +2465,7 @@ static int gsmld_output(struct gsm_mux *
+ return -ENOSPC;
+ }
+ if (debug & 4)
+- print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
+- data, len);
++ gsm_hex_dump_bytes(__func__, data, len);
+ return gsm->tty->ops->write(gsm->tty, data, len);
+ }
+
+@@ -2525,8 +2541,7 @@ static void gsmld_receive_buf(struct tty
+ char flags = TTY_NORMAL;
+
+ if (debug & 4)
+- print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
+- cp, count);
++ gsm_hex_dump_bytes(__func__, cp, count);
+
+ for (; count; count--, cp++) {
+ if (fp)